you may be much better, first going yourself on BVI
Best thing is probably to buy the dinghi right in town or from
the one of the marines, they have used and new ones.
If you go the other rout of shipping
it from somewhere, make sure
to say, that the boat is temporary at port and leaving soon.
We had to replace 3 air conditioners on our boat on BVI last year,
and because we were leaving after the repair, we had some kind of
custom fee brakes. I think normally was 20% of the price
and we end
up paying like 2% of the price
If this not stated in the declaration,
they have multiple customs, depends if the dinghi is coming from
the states or from somewhere else,and if it is coming by sea or air.
Best bet is buy your dinghi on the island or at ST.Thomas may be cheaper,
but again next you have to get through customs in BVI.